19. VB Project and Menu Design

Transcription

1 19. VB Project and Menu Design 19.1 Working with Projects As you develop an application, you work with a project to manage all the different files that make up the application. A VB project consists of: One project file that keeps track of all the components (.vbp). One file for each form (.frm). One binary data file for each form containing data properties of controls on the form (.frx). These files are not editable and are automatically generated for any.frm file that contains binary properties, such as Picture or Icon. Some optional files such as standard module (.bas) and class module (.cls) Structure of a VB Project Form Modules Form modules (.frm file name extension) can contain textual descriptions of the form and its controls, including their property settings. They can also contain form-level declarations of constants, variables, and external procedures, event procedures, and general procedures. Class Modules Class modules (.cls file name extension) are similar to form modules, except that they have no visible interface. You can use class modules to create your own objects, including both properties and methods. Standard Modules Standard modules (.bas file name extension) can contain public or module-level declarations of types, constraints, variables, and procedures. Standard Controls Standard controls are supplied by VB. Standard controls, such as the command button or frame control, are always included in the toolbox Menu Design So far, you might notice that all the simple applications in our class only consist of one form and several controls. However, for a relatively larger project, you should use Menu Editor to create new menus and menu bars. VB Project and Menu Design, Prepared by Dr. Jingxin Wang 1

2 Let me give you a simple example to show you how to create menus. Suppose we need to create the following menus in this example: File o Close o Exit Edit o Species o Stand Natural Planted Help o About o Content We are also required to do the following things: a. Close all window items in MDI form if the user clicks the Close menu. b. Exit the program if the user clicks Exit menu. c. Invoke species form if the user clicks the Species menu. d. Invoke About form if the user clicks About menu. What we need to do are as follows: (1) Start a new VB project (2) Add a MDI form to the project by clicking Add MDI form from Project menu (Figure 1). Figure 1. MDI form. (3) Create menus To display the Menu Editor, choose Menu Editor from the Tools menu (Figure 2). VB Project and Menu Design, Prepared by Dr. Jingxin Wang 2

3 Figure 2. Menu editor. Name this is the name you use to reference the menu control from code. Caption this is the text that appears on the control. Click OK button, the menus will be created on the top of MDI form (Figure 3). Figure 3. Menus. VB Project and Menu Design, Prepared by Dr. Jingxin Wang 3

4 (4) Now you need to add another form that will be used to edit species and display about information since form1 is already in the project. You can do that by clicking Add Form from Project menu. (5) Double-click menu item and add codes there. Private Sub mnuabout_click() Form2.Show Form2.Caption = "About My Program" Private Sub mnuclose_click() Unload Form1 Unload Form2 Private Sub mnuexit_click() End Private Sub mnuspecies_click() Form1.Show Form1.Caption = "Edit Species" Display a popup menu Private Sub MDIForm_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single) If Button = 2 Then MDIForm1.PopupMenu mnufile End If (6) In Project Explorer Window, right click your project, click property and then change the start object of your application to MDIForm1 (Figure 4). (7) Before you start to run the project, you need to set the form properties as listed in Table 1. (8) Run the project (Figure 5). i. Click Edit Species ii. Click Help About iii. Click Close iv. Click Exit VB Project and Menu Design, Prepared by Dr. Jingxin Wang 4

5 (9) Save your project. Table 1. Property settings of forms. Form Property Setting MDIForm1 WindowState 2 - Maximized Form1 MDIChild True BorderStyle 1 - FixedSingle Form2 MDIChild True BorderStyle 1 - FixedSingle Figure 4. Project properties. VB Project and Menu Design, Prepared by Dr. Jingxin Wang 5

6 Figure 5. Running the project. VB Project and Menu Design, Prepared by Dr. Jingxin Wang 6